Over the years, various techniques have been developed to help a person accurately aim a weapon such as a rifle. One common approach is to mount a sight or scope on the weapon. A person then uses the sight or scope to view an image of a scene that includes an intended target. Existing sights usually superimpose a reticle on the image of the scene. For example, the reticle may be in the form of crosshairs.
Under certain circumstances, including low levels of ambient light, it may be advantageous if the reticle is illuminated to increase its visibility. Various techniques have previously been developed for illuminating a reticle. Although these known techniques have been generally adequate for their intended purposes, they have not been satisfactory in all respects.